The widespread
destruction of tropical rainforest
ecosystems and the consequent extinction of numerous
plant and animal species is happening before we know
even the most basic facts about what we are losing.

5

Covering
only 6 percent of the Earth's surface,
tropical moist forests contain at least half of all species.
The abundant botanical resources of tropical forests
have already provided substantial medical advances; yet
only 1 percent of the known plant and animal species

10

have been carefully examined for their
medicinal
potentials. Meanwhile, 2 percent of the world's rainforests
are irreparably damaged each year. Scientists estimate
that, at the accelerating rate at which rainforests are now
being destroyed, as much as 20 or 25 percent of the

15

world's plant species will soon be extinct.
Approximately 7,000 medical compounds
prescribed by Western doctors are obtained from plants.
These drugs had an estimated retail value of US$ 43
billion some years ago. Seventy percent of the 3,000

20

plants identified by the United States
National Cancer
Institute as having potential anti-cancer properties are
characteristic of the rainforest. Tropical forest species
serve Western surgery and internal medicine in three
ways. First, extracts from organisms can be used directly

25

as drugs. For maladies ranging from persistent
headaches
to lethal contagions such as malaria, rainforest medicines
have provided modern society with a variety of cures and
pain relievers.
Secondly, chemical structures of forest
organisms

30

sometimes serve as models from which scientists
and
researchers can chemically synthesize drug compounds.
For example, the blueprint for aspirin comes from extracts
of willow trees found in the rainforest. Neostigmine, a
chemical obtained from the Calabar bean and used to

35

treat glaucoma in West Africa, also provides
the blueprint
for synthetic insecticides. However, the chemical
structures of most natural drugs are very complex, and
simple extraction is usually less expensive than synthesis.
Ninety percent of the prescription drugs that are based on

Tropical forests offer hope for safer contraceptives
for
both women and men. The exponential growth of world
population clearly demonstrates the need for more reliable
and effective birth control methods. Worldwide,
approximately 4,000 plant species have been shown to

50

offer contraceptive possibilities. The
rainforest also holds
secrets for safer pesticides for farmers. Two species of
potatoes have leaves that produce a sticky substance
that traps and kills predatory insects. This natural self-
defense mechanism could potentially reduce the need

55

for using pesticides on potatoes. Who knows what
other
tricks the rainforest might have up its leaves?

Mark the only correct statement about the structure
of Text 1.
(A) Paragraph 1 affirms that the world's population is powerless against
deforestation.
(B) Paragraph 2 warns about the destruction of rainforests and its valuable
resources.
(C) Paragraph 3 aims to inform the exact number of all plants identified
in tropical forests.
(D) Paragraph 4 explains in detail how insecticides can be obtained from
plants.
(E) Paragraph 5 lists the unhealthy or poisonous plants found in the rainforest.

In the sentence "yet only 1 percent of the known
plant and animal species " (lines 8-9), the word YET:
(A) adds an example.
(B) introduces a result.
(C) makes a comparison.
(D) expresses a contrast.
(E) provides a cause.

The only item that contains an adjective used in the superlative form
is:
(A) "The widespread destruction ( ) is happening before we even
know the most basic facts about what we are losing." (lines 1-4)
(B) "Covering only 6 percent of the Earth's surface, tropical moist
forests contain at least half of all species." (lines 5-6)
(C) "Scientists estimate that ( ) as much as 20 or 25 percent
of the world's plant species will soon be extinct." (lines 12-15)
(D) "However, the chemical structures of most natural drugs ( )
simple extraction is usually less expensive than synthesis." (lines
36-38)
(E) "Tropical forests offer hope for safer contraceptives for both
women and men." (lines 45-46)

Mark the only sentence that CANNOT be correctly completed with
the preposition FROM.
(A) Commercial sales of drugs derived _____ this one plant are about US$160
million a year.
(B) Madagascar's rosy periwinkle, a plant _____ Africa, provides two important
anti-tumor agents.
(C) Quinine, an aid in the cure of malaria, is an alkaloid extracted _____
the bark of the cinchona tree found in Latin America and Africa.
(D) _____ 1960, only 19 percent of Hodgkin's disease sufferers had a chance
for survival.
(E) Until recently, wild yams _____ Mexico and Guatemala provided the
world with its entire supply of diosgenin, an active ingredient in birth
control pills.

In the sentence "Who knows what other tricks the
rainforest might have up its leaves?" (lines 55-56), the author means
that:
(A) nobody will ever know how to decipher the enigmas of the rainforest.
(B) there must be a way of learning more about the rainforest puzzles.
(C) people doubt whether rainforest plants hide other mysteries.
(D) it is impossible to find out all the applications of tree leaves.
(E) it is possible that forest plants bring us additional surprises.

Mark the title that best expresses the main idea of Text 1.
(A) Daily Life in the Rainforest.
(B) How to Protect World Ecosystems.
(C) Diseases Caused by the Rainforest.
(D) Rainforests: Pharmacy to the World.
(E) Paradise Lost: The Devastated Rainforest.

Based on the quotation, we may infer that the author
finds television educating because:
(A) it teaches people how to read books as a solitary activity.
(B) it runs many advertisements of books and other cultural products.
(C) it makes him want to read a book in order to escape from TV shows.
(D) some of its programs encourage viewers to develop reading habits.
(E) there are more programs with instructional content than silly ones.